That's because another deal signed on the same day — a "road map" between the International Atomic Energy Agency and Iran — will allow the IAEA to confirm that Iran has responded to all of the agency's concerns regarding Tehran's past nuclear-weaponization efforts.

These disclosures are critical to the success of an agreement, as they allow international monitors to establish a baseline of Iranian nuclear-weapons research, experimentation, and expertise for future inspections.

Without knowledge of the scope and extent of Iran's program, it's difficult for the IAEA to eventually confirm that Iran's nuclear programs are for solely peaceful purposes.

Consequently, the two nuclear deals have a direct relationship: Without Iran and the IAEA following their road map, the inspection and verification mechanisms of the other nuclear deal can't work either.